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Rear mounted rad

Discussion in 'The Garage' started by Thumper, Mar 24, 2007.

  1. Thumper

    Thumper 1/2 ton status

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    Hiya guys! Its been a long time!
    Got some questions.
    I am mounting my rad in the rear of my hybrid S-10/K5 now with a Taurus electric fan. A couple reasons... mud avoidance, bigger rad, more engine bay room etc.
    My question is this:
    1. Will the stock water pump be sufficient to move the fluid back to the rad now? I am trying to limit the bends in my pipes, but the rad does sit a bit higher than the motor.
    2. Is it really necessary to limit the number of bends? Its a pain in the a$$, and most of the bends are way less than 90* but some have to be.
    3. I am thinking of keeping the stock clutch fan on the motor... to help with some air movement over the engine... do you think its really necessary? Another option I thought about is to mount a second electric fan in the hood.. just to move some air out of the engine bay. Thoughts? Experiences?
    Thanks guys.
    I just couldnt stay away from here when I have issues!
    Mike
     
  2. Confedneck79K30

    Confedneck79K30 3/4 ton status

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    not personally done, but a friend of mine has this done, he used an electric water pump, no fans underhood and ran the heck out of it with 5 broken pistons a couple weeks ago and had no problems... just a single electric fan on the 3" be cool out back...
    he mounted his straight up and down iirc as well if that matters
     
  3. gmc4cw

    gmc4cw 1/2 ton status GMOTM Winner

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    the clutch fan isn't going to provide any cooling and you have no way to turn it off if you ever do any water crossings.
     
  4. Thumper

    Thumper 1/2 ton status

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    Well, without a fan in the front at all, there will be zero air movement in the engine bay at wheeling speeds. I dont know how much the engine relies on air movement to cool (there must be some air cooling as well as liquid) but I suspect there might be a bit.
    Also, the biggest reason to turn off the fan for water crossings is to protect the rad... the rad isnt there any more. And also, the water would probably stop the clutch fan on its own, or at least slow it down. Not really an issue.
    Thanks for the inputs.
    Mike
     
  5. 76zimmer

    76zimmer Flyin Rat Premium Member GMOTM Winner

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    Just paint the engine flat black, I think that will do as much as airflow from an engine driven fan. As long as the coolant temp exiting the engine stays 210 or below, I think you'll have no problems temperature related. Just make sure the wiring is protected from high heat sources.
     
  6. YZEATER

    YZEATER 1/2 ton status

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    when the fan hits water, it'll throw it all over the ignition and carb. that's one reason to get rid of it.
     
  7. 85mudbogger

    85mudbogger 1/2 ton status

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    what are u gonna use as far as the pipeing to run back to the rad, ive been pondering this also, my dad did this awhile ago to our old chevy luv mud runner but seemed like he was fixin holes all the friggin time in the pipe runnin along the frame.
     
  8. cybrfire

    cybrfire 1 ton status Vendor GMOTM Winner

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    I have an aluminum rad in the back of my blazer. Plumbed it with 2" aluminum tubing. No fans in the engine compartment. I did wrap the headers to help keep heat down. twin 12" electrics on the radiator. Very few bends are sharp at all. Maybe 2 per side are near 90*.

    Rad is higher than the engine. Leaned slightly forward.

    I also used a Ford style aluminum radiator. That puts your ins and outs on the correct side when you turn it around.

    Capacity is huge. Something like 4-5 gallon system now.

    This is a cadillac 500 which are known to run hot.

    Started with a restrictor but will be adding a thermostat to help things get to operating temperature.
     
  9. 73k5blazer

    73k5blazer Unplug the matrix cable from the back of your head Premium Member

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    The engine does not rely on any air cooling, a fan under the hood is completely unessesary if you move the radiator out. If your that worried about, remove the seal that seals the back of the hood the firewall, that retains alot of heat, that'll leave a small gap there and let most heat escape naturally.
     
  10. Thumper

    Thumper 1/2 ton status

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    Well, as far as throwing water all over the ignition and carb... Dont you ever wash your engine? I run a snorkel for air intake, the rest of the carb can get as wet as it wants. The HEI ignition is pretty well sealed from GM itself, a splash wont ever affect it. However, I run a dielectric grease in all the plug wire connections and a small bead of vaseline around the bottom of the distributer, then even when its mostly under water (for a short time) I dont get any issues from water in there. The biggest problem is the reason Im doing all this in the first place. my clutch fan packed in a while ago, and instead of replacing the clutch right away, I bolted on an old flex fan I had laying around. As soon as I drove into the water deep enough, the fan propelled itself forward into the rad tearing a 3 core deep hole in the bottom of the rad, AND breaking off half of one blade. Thats why its nice to turn a fan off for water.
    Anyways, I have the project finished. The rad is in the back, with a large 2 speed Taurus electric fan is mounted on it. I used galvanized electric conduit for the piping 1 1/2". The bends I used some rad hose I had around plus a couple pieces I bought from NAPA that had some useful elbows etc on them. There are a couple of 90* bends, and the rad is above the engine quite a bit. I ran it off road a few times around my yard, with the thermostat removed for flow, and the fan off, it warms up fairly slowly but gets to 190ish within 10 minutes. Its still around +10C here so it will warm faster in the summer. I can turn the fan on low and in about 5 mins while still driving it drops to around 160. It seems to work fine. I am going to put the thermostat back in for a test, hopefully it will still flow good enough.
    And youre right... it holds a pile of coolant now hehe.
    Thanks for the replies.
    Later
    Mike
     

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